JP2004299663A - Suspension arm, forged suspension member, and forging die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forged suspension member that can be formed compactly in dimension of a ball joint section while securing strength, can have a long arm unit, and can be appropriately forged even when the arrangement of a parting line changes. <P>SOLUTION: The forged suspension member 1f is mounted to a supporting member constituting a suspension of an automobile via a stud bolt. A joint section 2f of the forged suspension member has one end surface section 3f, the other end surface section 4f, and a side surface section 5f. The parting line P1 on the joint section has, on the rim side of the one end surface section 3f defining a projecting side of the stud bolt, a vertical side surface CS or a vertical line formed in parallel with the neutral direction SN of the stud bolt. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a suspension arm used as a suspension member arranged around a wheel of an automobile or the like and attached via a stud bolt serving as an engagement structure, and a forged suspension for forming the suspension arm by machining. The present invention relates to a member and a forging die thereof.

  Generally, a vehicle suspension member such as a suspension arm attached to a support member such as a knuckle or a carrier supported on an axle side of an automobile through a joint structure joined to a ball stud bolt has a predetermined length. An arm portion, a ball joint portion for supporting the ball stud bolt at one end side of the arm portion, and a vehicle body side engaging portion engaged with a vehicle body such as a sub member at the other end side of the arm portion , And various things have been proposed.

  For example, as a suspension arm, in order to improve steering stability, the distance between fulcrums from one ball joint part to the other ball joint part (vehicle side engaging part) is increased, It is known that by making the center of the joint of the portion closer to the center of the tire, the scrub radius (the distance between the intersections of the line connecting the center line of the wheel and the upper and lower joints on the tire contact surface) can be reduced, and torque steer can be reduced. Therefore, it is desired to form the suspension arm so as to reduce the joint dimension.

  Further, since the installation environment in which the suspension arm is installed is near the wheels of the automobile, the installation space is limited, and there is a restriction when using a suspension arm that realizes the configuration of the above-described arm portion. Therefore, it is desired to increase the degree of freedom in design by reducing the shape of the ball joint in the suspension arm.

  On the other hand, the suspension arm has a material formed of steel, and in a configuration provided with a steel ball joint portion, the ball joint portion tends to be large because it is formed by press molding (for example, Patent Document 1). Therefore, conventionally, a suspension arm is formed of an aluminum alloy instead of a steel material, and the ball joint portion and the arm portion are integrated, the ball joint portion is small, the arm portion is formed long, and the strength and weight are increased. In view of this, there is a proposal that is superior to steel (for example, Patent Document 2).

  Also, as shown in FIG. 9, the suspension arm made of an aluminum alloy has the ball joint portion 102 formed integrally with the arm portion 106 by forging, and then the ball portion 134 of the ball stud bolt 133 is inserted. Are inserted, and the ball stud bolt 133 is inserted and assembled with an intervening member 138 composed of a plurality of parts (not shown in the drawing and shown as one part) interposed therebetween.

  When the suspension arm 100 is forged, a parting line PL is formed in the arm portion 106 and the ball joint portion 102, and the parting run PL is disposed at a substantially central position of the ball joint portion 102. It is formed so that the center of the side portion 105 protrudes.

  The arm and the ball joint are each forged with a machining allowance and a draft. Further, since a force is applied to the ball joint portion in the direction in which the ball portion of the ball stud bolt enters and exits while the vehicle is traveling, for example, a large stress is applied to the ball joint portion. However, a certain material volume must be secured.

  In a forging die of a suspension arm manufactured by forging, a parting surface on which the parting line is formed is set in a horizontal direction which is a direction orthogonal to a forging press direction. For this reason, in the forging die, the position substantially at the center with respect to the thickness direction on the side surface of the suspension arm becomes the mold splitting surface arranged in the horizontal direction, and the arm portion and the ball joint portion of the suspension arm are aligned with respect to the thickness direction. The parting line is formed substantially at the center.

JP-A-10-37944 (paragraphs 0013 to 0017) JP-A-2000-355206 (paragraph numbers 0010 to 0015)

However, the conventional structure of a suspension arm or a forging die formed of an aluminum alloy has the following problems.
In a suspension arm formed by conventional forging, the parting line is located approximately at the center in the thickness direction on the side surfaces of the ball joint and the arm portion. It is necessary to increase the size of the ball joint part because it is necessary to provide the dimension addition part necessary for the draft angle so as to increase the wall thickness.

  In addition, in the conventional suspension arm, the parting line is disposed substantially at the center in the thickness direction on the side surfaces of the ball joint portion and the arm portion. In addition to the increased wall thickness, it has been necessary to add and consider a dimension for securing an interference range with the wheel when the wheel is joined to a support member constituting a suspension of the wheel. For this reason, the suspension arm is restricted from bringing the ball joint portion close to the wheel, and the degree of freedom in design is impaired.

  Further, in the conventional suspension arm configuration, since the parting line where the grain flow is concentrated and the weakest part is located almost at the center, it is disadvantageous for the pull-out load of the stud bolt, and there is a limit to downsizing.

  The present invention has been made in view of the above-described problems, and a forged suspension member capable of securing strength with respect to dimensions of a ball joint portion, being compactly formed, and having a large arm portion length, Still another object of the present invention is to provide a forging die for a forged suspension member that can perform appropriate forging even if the arrangement of the parting line changes.

  The present invention has the following configuration to achieve the above object. That is, the forged suspension member according to the present invention is a forged suspension member having a parting line at a predetermined position attached to a support member constituting a vehicle suspension via a stud bolt, wherein the forged suspension member includes an arm portion, A ball joint portion provided at one end of the arm portion and provided at a position supported by the stud bolt; and a vehicle body-side engaging portion provided at a position provided at the other end of the arm portion and engaged with the vehicle body. The ball joint portion includes one end face portion and the other end face portion arranged at positions facing each other, and a side face portion formed over both end face portions, and a parting line in the ball joint portion is provided. And the arm portion at the peripheral edge of the one end surface portion where the stud bolt protrudes. A vertical line formed from the target position to the other end surface perpendicularly to the one end surface portion. A configuration including a side surface or a vertical line, and an inclined side surface that is formed adjacent to the vertical side surface or the vertical line and inclined at a predetermined angle toward the one end surface portion or the other end surface portion with the parting line as a boundary. (Claim 1).

  With this configuration, the forged suspension member has a structure in which, in the ball joint portion, the concentration of the grain flow at the parting line position is such that the peripheral portion of the end surface portion is the side portion that is farthest from the arm portion. , And the pull-out load of the stud bolt can be expected to be improved by 10% as compared with the conventional structure of the almost central parting line. Also, since the forged suspension member has a vertical side surface from the target position of the parting line on the side surface portion of the ball joint portion, a portion protruding as compared with the ball joint portion having the conventional configuration, that is, an increase in draft, is provided. It is possible to reduce the wall thickness and the remaining burr length.

  Further, a suspension arm having a ball joint portion which is rotatably mounted on a support member supported on the axle side of the automobile via stud bolts and avoids an interference region with the axle side component is formed by machining. The forged suspension member includes an arm portion, a ball joint portion provided at one end of the arm portion, a vehicle body side engaging portion provided at the other end of the arm portion, and the arm portion. A parting line continuously formed at a predetermined position of the ball joint portion and the vehicle body side engaging portion, the ball joint portion has one end face portion, and the other end face portion facing the one end face portion, The ball joint portion including the other end surface portion and a side surface portion formed over the one end surface portion. The swing line is formed at a position in the range that becomes the interference area on the side surface portion, on one of the peripheral sides of the one end surface portion or the other end surface portion, toward a preset target position of the side surface portion. (Claim 2).

  With this configuration, the forged suspension member forms a grain flow toward the target position on the peripheral side on one of the one end surface portion and the other end surface portion, and furthermore, from the arm portion in the interference region. The side surface of the ball joint, which is the far end, is a vertical line or a vertical surface without protrusion.

  In addition, in the forged suspension member, the ball joint section may be configured such that a cross section at a position along the parting line is a perfect circle or an approximate circle with respect to a neutral direction of the stud bolt or a direction orthogonal to the one end surface. A compound having a perfect circular shape, and having the inclined side surface having a draft angle of inclination inclined from the parting line, and having a plurality of curvatures surrounded by the inclined side surface and the vertical side surface or the vertical line. The configuration is provided with the both end face portions having a circular curvature shape (claim 3).

  With such a configuration, the forged suspension member can obtain the strength required for the shape of the ball joint portion with the minimum necessary material volume, and is advantageous for the interference range on the wheel of the automobile, and has a scrub Radius can be reduced.

Further, in the forged suspension member, the target position is formed at a position on the vertical side surface or the vertical line position where there is no increase in thickness due to draft angle.
With such a configuration, the forged suspension member can obtain the strength necessary for the shape of the ball joint portion with the minimum necessary material volume in a predetermined range of the target position where the parting line satisfies a certain condition. it can.

Further, in the forged suspension member, the parting line in the ball joint portion may be linear from the parting line in the arm portion to the target position, or may be a curved line from the parting line in the arm portion. It is configured to be formed either linearly to the target position or linearly from the position where the parting line of the arm portion is extended to the target position (claim 5).
With this configuration, the parting line can be set according to the form of the ball joint portion in the forged suspension member.

Further, in the forged suspension member, the arm part is configured such that the parting line is formed at an arbitrary position from an upper end to a lower end on a side surface thereof (claim 6).
With such a configuration, the forged suspension member can be set such that the parting line does not exist in a portion where the generated stress is large on the side surface even in the arm portion, and the strength can be reduced while maintaining the strength.

Further, in the forged suspension member, a vertical direction of the vertical side surface or the vertical line is a direction parallel to a neutral direction of the stud bolt.
With this configuration, the forged suspension member can appropriately cope with the engagement of the stud bolt.

In the forged suspension member, a target position of the ball joint on the parting line is arranged at a position removed by machining.
With such a configuration, in the forged suspension member, a vertical surface or a side surface that is a vertical line is the outermost at a position that is an interference region of the ball joint.

  A suspension arm formed by machining from the forged suspension member has a radius of a ball ball diameter of the stud bolt as R1, and a distance from a center of the ball joint to an outermost part in an interference region of the ball joint. Is R2, the ball joint portion is formed at a ratio represented by 1.2 <R2 / R1 ≦ 1.9. (Claim 9) With this configuration, the suspension arm can maintain the strength of the ball joint portion and expand the degree of freedom in design.

In the suspension, the stud bolt may have a pull-out strength and a push-out strength of 25 kN or more. By setting the pull-out strength of the suspension arm to 25 kN or more in this way, it becomes possible to counter shocks during traveling.
Further, in the suspension arm, the forged suspension member is made of an Al-Mg-Si-based aluminum alloy having an average area ratio of sub-crystal grains in the structure of 60% or more and a 0.2% proof stress of 290 MPa or more. (Claim 11).
With this configuration, the suspension arm is made of a high-strength aluminum alloy, and the wall thickness of the ball joint can be reduced while maintaining the holding force of the ball portion.

  Further, in the forging die according to the present invention, in the forging die for forging a forged suspension member having the above-described configuration, a parting line in the ball joint portion may be a peripheral side of the one end surface portion or a periphery of the other end surface portion. On the edge side, a parting surface is provided so as to be formed from the parting line of the arm portion toward a target position of a side surface portion which is the farthest end portion.

  With this configuration, in the forging die of the forged suspension member, since the parting surface is provided at a predetermined position, it is possible to obtain the strength required for the shape of the ball joint portion with the minimum necessary material volume. A forged suspension member that can be provided.

  Further, in the forging die of the forged suspension member having the above-described structure, the parting line in the ball joint portion is located at the peripheral edge of one end surface portion or the peripheral edge side of the other end surface portion, and is located at the farthest end from the parting line of the arm portion. The mold surface is provided so as to be formed toward the target position of the side surface portion, and the mold surface is set to be inclined at a predetermined angle with respect to the forging press direction in the arm portion and the ball joint portion, The side surface portion at the target position is set to be in a direction perpendicular to the one end surface portion of the ball joint portion or to be parallel to the neutral direction of the stud bolt (claim). 13).

  With this configuration, the forging die for the forged suspension member can minimize the strength required for the shape of the ball joint without increasing the draft angle, even for forged suspension members of different forms. Material volume.

According to the forged suspension member and the forged die thereof according to the present invention, the following excellent effects can be obtained.
At the target position, which is the farthest end of the ball joint, the forged suspension member has no wall thickness increase due to draft, and its vertical side surface (vertical line) is perpendicular to both end surfaces or parallel to the neutral direction of the stud bolt. Obtained and can be miniaturized.

  In addition, the forged suspension member can be reduced in strength while maintaining the strength, since there is no parting line in a portion of the ball joint portion where the generated stress is large on the side surface. Furthermore, since the residual burr length is removed by machining in the finished product, it is not necessary to consider the residual burr length in the tire interference region. Therefore, the joint center of the ball joint can be brought closer to the tire center, and the design can be reduced. It is possible to provide a forged suspension member having a greater degree of freedom and a smaller scrub radius.

The forged suspension member can obtain the strength required for the shape of the ball joint portion with the minimum necessary material volume, and is advantageous in terms of draft angle and remaining burr length with respect to the interference range in the wheel of the automobile. .
In addition, the forged suspension member is provided with one of a predetermined parting line under a certain condition in the ball joint part, so that the ball can be downsized corresponding to the form of the ball joint part. Joints can be set.

  Further, the forged suspension member can obtain the strength required for the shape of the ball joint portion with the minimum necessary material volume. Further, in the forged suspension member, the parting line is formed at an arbitrary position from the upper end side to the lower end side of the side surface of the arm portion, so that the parting line does not exist in a portion where the generated stress is large on the side surface. It is possible to maintain the strength and make the whole smaller.

  The suspension arm regulates the radius of the ball diameter at the ball portion of the ball stud bolt and the distance to the outermost diameter of the ball joint portion so as to be within a predetermined range, so that the strength of the ball joint portion is maintained. The degree of freedom of design for achieving miniaturization in the state can be expanded. Further, in the suspension arm, by using a high-strength aluminum material or in a state where the conditions for the pull-out strength and the push-out strength are satisfied, the side wall of the ball joint can be made slimmer.

  In the forging die of the forged suspension member, the parting line in the ball joint is located on the peripheral side of the end face that is the projecting side of the stud bolt, and the position of the side face that is the farthest end from the arm. By providing the mold parting surface so as to be formed toward the forged suspension member, it is possible to provide a forged suspension member that can be reduced while maintaining the pull-out strength of the ball joint portion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a mounting position of a forged suspension arm with a part thereof omitted, FIG. 2A is a side view showing a state in which a part of the suspension arm is broken, and FIG. 3) is a cross-sectional view schematically illustrating an example of a forging die of a suspension arm, FIG. 3A is a side view schematically illustrating a ball joint portion of the suspension arm, and FIG. 3B is a ball joint of the suspension arm. FIG. 4A is a side view schematically showing a grain flow in a ball joint of a suspension arm, and FIG. 4B is a side view schematically showing a grain flow in a ball joint of a conventional suspension arm. FIG. In each of the drawings, the reference numerals indicating the forged suspension members will be described by adding “f” to the reference numerals assigned to the suspension arms.

  As shown in FIGS. 1 and 5A and 5B, the suspension arm 1 has an arm 6, a joint 2 formed at one end of the arm 6, and a second end of the arm 6. And a vehicle body side engaging portion 9 formed. The suspension arm 1 is forged as a forged suspension member 1f (see FIG. 3) with an aluminum alloy or the like, and then machined from the forged suspension member 1f (see FIG. 3). The joint portion 2 is rotatably supported with respect to an interference area (not shown) via a ball stud bolt (stud bolt) 33 of a support member (knuckle, carrier, etc.) 32 constituting the suspension, and the vehicle body side The engagement portion 9 is engaged with and supported by an engagement position on the vehicle body side (not shown) of the axle 31. The interference region (not shown) is described as an example in a range of 100 degrees from the center of the ball joint 2f (see FIG. 3) to the left and right as an example, but is not limited to this range. The axle-side parts that interfere with the interference area refer to parts such as brake disks and wheels.

  As shown in FIG. 2A, the ball stud bolt 33 interposed between the support member 32 (see FIG. 1) and the suspension arm 1 is screwed with a nut 35 to be engaged with the support member 32. And a body portion 36 continuing from the screw portion 35, and a ball portion 34 provided at an end of the body portion 36. When the ball stud bolt 33 is supported by the ball joint portion 2, the ball portion 34 extends 360 degrees in the neutral direction (perpendicular to the one end surface portion 3) SN (see FIG. 3). , And is engaged and supported in the ball joint portion 2 through an intervening member 38 composed of a plurality of parts (here, shown as one part).

  As shown in FIGS. 5A and 5B, the suspension arm 1 has a complicated shape with non-axisymmetric wheels, such as one having two body-side engaging portions 9 or one having only one. Since it often has the same strength and corrosion resistance as a ferrous material, A6061 or a 6000-based derivative thereof, and an aluminum alloy such as a high-strength aluminum alloy are used. As an example of the high-strength aluminum alloy material, an Al-Mg-Si-based aluminum alloy having an average area ratio of subcrystal grains in the structure of 60% or more and a 0.2% proof stress of 290 MPa or more is given as an example.

  In aluminum alloys, the proportion of sub-crystal grains in the forged material structure has a greater effect on the higher strength, higher toughness, and higher corrosion resistance of the forged material than the finer grain size in the forged material structure (contribution). I do. That is, by increasing the proportion of subcrystal grains in the structure of the forged material, it is possible to achieve high strength, high toughness, and high corrosion resistance of the forged material with good reproducibility. In other words, even if the average crystal grain size of the forged material structure is reduced to 50 to 80 μm by hot forging, if the average area ratio of subcrystal grains finer than the crystal grain size is small in the forged material structure, In addition, high strength and high toughness of the forged material and high corrosion resistance cannot be realized with good reproducibility.

  Therefore, if the average area ratio of the sub-crystal grains in the forged material structure is 60% or more, the 0.2% proof stress of the forged material can be 290 MPa or more, and the stress corrosion cracking resistance can be improved. Further, when the average area ratio of the sub-crystal grains is preferably 90% or more, the 0.2% proof stress of the forged material can be increased to 350 MPa or more together with the stress corrosion cracking resistance.

  The measurement of the sub-crystal grains of this high-strength aluminum alloy material is performed by electrolytically etching the structure measurement cross section of the forged material, and in particular, by sharpening the sub-crystal grain boundaries and the crystal grain boundaries. It is performed after discriminating between a boundary and a sub-crystal grain. At this time, in order to take into account the variation due to the forged material, the measurement (collection of data) is performed at 20 visual fields at different locations where the strength and corrosion resistance of each forged material are required. Then, the average area ratio of the sub-crystal grains is measured by visual or image processing the area occupied by the sub-crystal grains for each visual field, and the area ratio of the sub-crystal grains to one visual field area is calculated. The area ratios of the subcrystal grains in the 20 visual fields are averaged to obtain the average area ratio of the subcrystal grains (%).

  Then, as shown in FIGS. 2A and 2B (see FIG. 7), the suspension arm 1 mechanically forges a forged suspension member 1f forged by a forging die 10 having an upper die 11 and a lower die 12. It is formed by processing. Note that FIG. 2A shows that the neutral direction SN of the ball stud bolt 33 is perpendicular to the arm plane. The forging die 10 is configured to have a mold parting surface 13 inclined at a predetermined angle at the positions of the arm 6 and the ball joint 2.

  In the forging die 10, the parting line P2 of the arm portion 6 is formed with the parting surface 13 so as to be formed at the center position in the thickness direction E on the side surface of the arm portion 6f. It is set to be inclined at a predetermined angle with respect to the direction T. Further, in the forging die 10, the parting line P1 of the ball joint portion 2f is formed from the arm portion 6f of the side surface portion 5f toward the farthest end portion at the periphery of the one end surface portion 3f, and in the forging press direction T. On the other hand, the mold parting surface 13 is configured to be inclined at a predetermined angle.

  In addition, as shown in FIG. 2B, the parting line P2 of the arm portion 6f is set so that the inclination angle θ1 is set in the range of 0.5 to 5 degrees with respect to the horizontal line portion of the parting surface 13. Is formed with a parting line 13. In addition, the position of the farthest end (side surface 5f) of the ball joint 2f is set so that the inclination angle θ2 is in the range of 0.5 to 5 degrees with respect to the vertical line (forging press direction T). ing. The side end portion of the ball joint portion 2f (the outline of the side surface portion 5f, the position indicated by the line of the inclination angle θ2) is parallel to the neutral direction SN of the ball stud bolt 33 (see FIG. 2A). Is set to

  As shown in FIG. 3, the parting line PL formed in the arm 6f and the ball joint 2f is a parting line P2 in the arm 6f, and has an arbitrary part from the upper end to the lower end in the thickness direction E on the side surface thereof. It is formed at a position, but here, it is formed so as to be located at the center. Further, the parting line PL is a parting line P1 in the ball joint 2f, at a peripheral position of the one end face 3f, at a target position (arm) of the side face 5f which is the farthest end from the parting line P2 of the arm 6f. The portion 6 is formed in a state of being inclined toward an extension of the central axis in the width direction W of the portion 6 toward the peripheral edge position (the peripheral edge position of the one end surface portion 3f) S orthogonal to the vertical direction. The target position S which is the end of the parting line P1 in the ball joint portion 2f is a position where the wall thickness does not increase due to the draft, and is an allowable range in the dimension d which is vertical in the side surface portion 5f.

  In addition, as shown in FIG. 3B, the target position S is, in other words, on the center axis in the width direction W of the ball joint 2f or the arm 6f (when formed linearly) and on the other end surface. It is formed at the position of the side surface portion 5f which is on a vertical line (parallel to the stud bolt neutral direction SN) continuous over the portion 4f and the one end surface portion 3f, and as shown in FIG. The range indicated by the dimension d moved in the vertical direction (parallel to the stud bolt neutral direction SN) is the allowable range. The target position S is a vertical side surface CS as shown in FIG.

  When the arm portion 6f is curved and provided with a ball joint portion 2f at one end thereof, the vertical side surface of the side portion 5f extends on an extension line passing through the axial direction of the arm 6f and the center position of the one end surface portion 3f. From the intersection with the center line (vertical line) of CS, the allowable range of the dimension d is obtained. Incidentally, as shown in FIGS. 1 and 2, when the ball joint portion 2 is actually engaged with the ball stud bolt 33, a vertical side (vertical line) CS is formed at a position related to the interference range with the wheel 30. The target position S is set at a position. As shown in FIG. 3B, the target position S is located at both ends of an edge line parallel to the one end surface portion 3f in the range indicated by the vertical side surface CS, that is, the parting line P2 from the arm portion 6f. May be continuous with the left and right target positions S1 and S2. When the parting line P1 is at the target positions S1 and S2, the side surface portion 5f inside the target positions S1 and S2 is a vertical side surface.

  As shown in FIG. 3 (a), this dimension d is the range of the radius portion which is a corner portion originally formed on the periphery of the ball joint portion 2f, and the target position S is lowered from the upper end to the other end surface portion 4f side. When the position becomes the position, it is preferable that the range is from the target position S to a position where no draft is formed toward the one end surface portion 3f. The dimension d may be an allowable range as long as the ball joint 2f can be made smaller than the conventional parting line PL provided at the center. 3B, the target position S is shifted to the arm portion 6f side on a center line that is continuous with the center line of the arm portion 6f in the width direction W. It suffices if the vertical side surface (vertical line) can be formed substantially on the side surface portion 5f after machining.

  Further, as shown in FIG. 3, in the design stage of the ball joint 2f, the arrangement of the parting line PL is specified first, and the planar shapes of the one end face 3f and the other end face 4f are specified. The ball joint 2f is formed such that its cross-sectional shape at a position along the parting line PL is a perfect circle when viewed from the neutral direction SN (a direction orthogonal to the plane of the one end surface 3). I have. The planar shape of the one end surface portion 3f of the ball joint portion 2 has a cone having a draft N (see FIG. 3B) with respect to the forging press direction T with the cross-sectional shape along the parting line PL as the bottom surface. Is imagined, the plane of the imaginary cone cut at the plane position of the one end face portion 3f and the stud bolt neutral direction of the vertical side surface (vertical line) CS set in a range condition not protruding from the imaginary cone It is formed in a shape parallel to SN. The one end face 3f is formed in a compound curvature circular shape having a plurality of curvatures when viewed from the neutral direction SN.

  Similarly, the planar shape of the other end surface portion 4f has a draft N (see FIGS. 3A and 3B) with a cross-sectional shape along the parting line PL as a bottom surface and a vertical side surface (vertical line). When a cone provided with CS is imagined, the imaginary cone is formed on a plane cut at the plane position of the other end face 4f, and has a compound curvature circular shape including a plurality of curvatures when viewed from the neutral direction SN. Is formed.

  As shown in FIGS. 3A and 3B, the ball joint portion 2f has a side surface portion 5f formed so that the side surface portion 5f extends in the vertical direction of the target position S across the one end surface portion 3f and the other end surface portion 4f. A side surface (vertical line) CS (parallel to the neutral direction SN of the ball stud bolt 33) and an inclined side surface KS adjacent to the vertical side surface CS and having a draft angle N with respect to the forging press direction T. ing. Note that the inclined side surfaces KS are inclined in opposite directions with respect to the parting line PL (P1). No draft N is formed on the vertical side surface (vertical line) CS. A vertical side surface (vertical line) CS in the side surface portion 5f of the ball joint portion 2f is formed in a vertical direction from the target position S and has a surface having a predetermined width, or a linear shape having almost no width. It shows the case.

  Further, as shown in FIG. 3A, the draft (the inclination angle of the inclined side surface 5f) of the parting line PL from the parting line PL toward the one end surface portion 3f and the other end surface portion 4f is also set to 0. It can be in the range of 5 to 5 degrees, preferably in the range of 0.5 to 1.5 degrees.

  Further, in the suspension arm 1f forged by the forging die 10, as shown in FIG. 4A, the flow of the grain flow GF is formed toward the upper end position of the side surface 5f of the ball joint 2f. Will be. In this way, with the configuration shown in FIG. 4 (a), the flow of the grain flow GF is pulled out of the ball stud bolt 33 as compared with the conventional state as shown in FIG. 4 (b). Strength (strength) can be improved (please make sure to enter a numerical value).

  As shown in FIGS. 3A and 3B, when the ball joint 2f is machined so that the ball stud bolt 33 (see FIG. 2) can be engaged and supported, the ball joint 2f is hatched. Since the indicated area (surplus portion) F is omitted, the surplus length D of the draft can be reduced. Therefore, the center of the joint can be made closer to the center of the wheel for the size reduced by the ball joint 2f. When the arm 6f is configured to be long, it is necessary to reinforce the arm 6f.

  As shown in FIG. 3A, the suspension arm 1f is machined as indicated by a virtual line, and is formed in a state as shown in FIG. In the ball joint portion 2 of the suspension arm 1, the opening portion 3a of the one end surface portion 3 penetrates through the opening portion 4a of the other end surface portion 4, and the ball portion 34 of the ball stud bolt 33 is inserted, and is composed of a plurality of parts. It is formed so that it can be engaged and supported via the intervening member 38. Further, in the ball joint portion 2, a step portion is formed slightly upward from the center of the side surface portion 5 to form a locking portion 5b, and the dust cover 37 is engaged with the locking portion 5b. .

  Further, as shown in FIG. 2, the suspension arm 1 formed by predetermined machining or the like from the forged suspension member 1 f forged in the above-described configuration has a radius of the ball diameter of the ball portion 34 of the ball stud bolt 33. When R1 and the distance R2 from the center of the ball portion 34 of the ball joint portion 2 to the outermost portion are within the range of 1.2 <R2 / R1 ≦ 1.9, the ball joint portion 2 Is formed.

  This R2 / R1 is related to the degree of freedom and the strength of the design of the ball joint portion 2. As R2 / R1 decreases (the value of R1 increases), the degree of freedom of the design increases, but the strength of the joint portion 2 increases. In particular, if it exceeds 1.9, the required strength cannot be reliably obtained. Further, when R2 / R1 increases (when the value of R2 increases), the strength of the joint portion 2 increases, but the degree of freedom of design is narrowed. Will be hindered.

  Here, the pull-out strength and the push-out strength of the ball joint 2 configured to satisfy 1.2 <R2 / R1 ≦ 1.9 are set to be 25 kN or more here. If the pull-out strength and the push-out strength of the ball joint portion 2 are less than 25 kN, the ball portion 34 may come off from the ball joint portion 2 when running while mounted on the axle side. I am trying to become. In particular, by using the high-strength aluminum alloy described above and setting the parting line PL in the ball joint 2f at a predetermined position, the strength of the machined ball joint 2 can be maintained and reduced in size. Can be done smoothly.

  As shown in FIG. 1, the suspension arm 1 has a burr surface removed at the position facing the wheel 30 side during machining, so that the suspension arm 1 is compared with a conventional ball joint portion in which a parting line PL is formed at the center. Thus, it is not necessary to consider the remaining burr length in the tire interference area, and the joint center of the ball joint 2 can be made closer to the center of the tire. The cross-sectional shape of the arm portion 6 of the suspension arm 1 may be formed in a U-shape, an H-shape, or the like.

  Further, as shown in FIG. 6 (a), at the parting line PL, the connecting portion between the arm portion 6f and the ball joint portion 2f is formed so as to have a gentle radius (curve) so as to be positioned with respect to the target position S. May be configured to be linear. Further, as shown in FIG. 6B, the parting line PL extends linearly from the position of the arm 6f to a predetermined position of the ball joint 2f, and is formed linearly toward the target position S. A configuration may be adopted. At this time, the connection portion may be configured to have a gentle R as described above (not shown). When the ball joint 2f is cut along the parting line, the parting line PL is perpendicular to the one end face 3f or the other end face 4f, or the ball stud bolt 33 (see FIG. 2). Is not particularly limited as long as it is a perfect circle when viewed from the neutral direction SN.

  As shown in FIG. 3, as the suspension arm 1, the parting line PL has been described as being arranged at the center in the thickness direction on the side surface of the arm 6, but the thickness at the upper end side or the lower end side of the side surface is described. It may be arranged as an arbitrary position in the range of the direction E. Here, it is formed so as to be on the upper end side and the lower end side, and the side surface portion which is the farthest end portion from the arm portion 6 at the periphery of the one end surface portion 3 The structure of the parting line PL1 and the parting line PL2 formed toward the position 5 may be adopted.

  Further, as shown in FIGS. 7A and 7B, the suspension arm 1Af may be configured such that the arm 6A and the ball joint 2A are connected at a predetermined inclination angle. In addition, about the structure similar to FIG.2 (a), (b), "A" is attached after the same code | symbol (For a forged suspension member, "f" is added after "A"). Is omitted.

  As shown in FIG. 7B, the forging die 10A is configured such that the cutting surface 13A of the upper die 11A and the lower die 12A is on a horizontal line orthogonal to the forging press direction T at the center. ing. As shown in FIG. 7 (a), the parting line PL in the suspension arm 1A is formed at the center position in the thickness direction E on the side surface of the arm 6A, and the one end surface 3A is formed in the ball joint 2A. Is formed from the parting line P2 of the arm 6A toward the target position S (see FIG. 3) of the side surface 5A, which is the farthest end.

  As shown in FIG. 7B, in the forging die 10A, the inclination angle θ3 between the end of the ball joint 2Af and the vertical line is 0.5 to 5 degrees or more. It is set in the range. Further, the inclination angle θ4 between the arm 6Af and the ball joint 2Af is set within a predetermined inclination angle range. Also, the side end portion of the ball joint 2Af (the outline of the side surface 5Af, the position indicated by the line of the inclination angle θ3) is parallel to the neutral direction SN of the ball stud bolt 33 (see FIG. 7A). Is set to

  In the case of forging with the forging die 10A shown in FIG. 7B, as shown in FIG. 8, the burr outflow direction is changed from the state shown in FIG. 8A to the state shown in FIG. You can change and forge. In other words, in FIG. 8A, the outflow direction Bf of the burr from the side surface portion 5f of the ball joint portion 2f is, for example, a horizontal direction which is a direction orthogonal to the forging press direction. On the other hand, in FIG. 8 (b), the position of the set parting line (not shown) is slightly changed without changing the forging posture. Bf is set in a direction inclined at a predetermined angle from the horizontal direction to the perpendicular (forging press direction) side. In this way, by adjusting the burr outflow direction Bf in combination with the arrangement of the parting line P1 (see FIG. 3), when the forged suspension member 1f is machined, particularly when caulking is performed. Thus, it is possible to provide a suspension arm 1 (see FIG. 2) that improves the formability of the caulking process and is effective for improving the punching strength.

  Further, as shown in FIG. 3, the range in the thickness direction of the ball joint portion 2 f where the target position S is formed is within the interference range when the forged suspension member 1 f is formed on the suspension arm 1 by machining. It is more preferable that the position is within a range that is removed by processing. That is, as shown by the imaginary line in FIG. 3, the parting line P1 is located within the range where the parting line P1 is processed and removed at the farthest end (position) from the arm 6f or the side surface 5f of the ball joint 2f which is an interference area. By doing so, a vertical side surface can be secured in the side surface portion 5f.

  In the above description, both end portions 3 and 4 (3f, 4f) of the ball joint 2 (2f) are configured to be parallel to each other, but need not be parallel. When both end portions 3 and 4 are not parallel to each other, a vertical plane CS or a vertical line is formed on the side surface in parallel with the neutral direction SN of the ball stud bolt 33. Alternatively, when both end surfaces 3 and 4 are not parallel to each other, a vertical plane CS or a vertical line is formed on the side surface along a vertical direction orthogonal to the plane of the one end surface 3.

FIG. 3 is a partially omitted cross-sectional view showing a mounting position of a suspension arm according to the present invention. (A) is a side view showing a state in which a part of the suspension arm according to the present invention is broken, and (b) is a sectional view schematically showing an example of a forging die of the suspension arm shown in (a). . (A) is a side view schematically showing a ball joint part of the suspension arm according to the present invention, and (b) is a bottom view schematically showing the ball joint part of the suspension arm according to the present invention. (A) is a side view schematically showing a grain flow in a ball joint portion of a suspension arm according to the present invention, and (b) is a side view schematically showing a grain flow in a ball joint portion of a conventional suspension arm. . (A), (b) is a top view which shows typically the whole suspension arm concerning this invention as an example, respectively. (A), (b) is a schematic diagram which respectively shows the other form of the parting line of the suspension arm concerning this invention. (A) is a side view showing a partially broken state in another configuration of the forged suspension arm according to the present invention, and (b) schematically shows an example of a forging die of the suspension arm shown in (a). FIG. (A), (b) is a schematic diagram which shows the state which changed the outflow direction of the burr | burr in the forged suspension member concerning this invention. It is sectional drawing which shows the state which fractured the ball joint part of the conventional forged suspension arm.

Explanation of reference numerals

1 suspension arm 1f forged suspension member 2 ball joint 2f ball joint (forged suspension member)
3 One end face 3f One end face (forged suspension member)
4 Other end 4f Other end (forged suspension member)
5 Side section 5f Side section (forged suspension member)
6 Arm 6f Arm (forged suspension member)
DESCRIPTION OF SYMBOLS 10 Forging die 11 Upper die 12 Lower die 13 Molding surface 30 Wheel 31 Axle 32 Supporting member 33 Ball stud bolt (stud bolt)
34 Ball part 35 Screw part 36 Body part 37 Dust cover 38 Intermediate member SL Vertical line GF Grain flow N Draft PL Parting line (whole)
P1 parting line (ball joint)
P2 parting line (arm)
R1 Radius of ball diameter R2 Outermost SN of ball joint part Neutral direction (of ball stud bolt)
T Forging press direction

Claims (13)

In a forged suspension member having a parting line at a predetermined position attached to a support member constituting a vehicle suspension via a stud bolt,
The forged suspension member has an arm portion, a ball joint portion provided at one end of the arm portion and provided at a position supported by the stud bolt, and is provided at the other end of the arm portion and engaged with the vehicle body. A vehicle-side engagement portion provided at a position,
The ball joint portion includes one end surface portion and the other end surface portion arranged at positions facing each other, and a side surface portion formed over the both end surface portions,
A parting line in the ball joint portion is formed toward a target position of the side surface portion, which is an end portion far from the parting line of the arm portion, on a peripheral edge of one end surface portion that is a projecting side of the stud bolt,
The side surface portion includes a vertical side surface or a vertical line formed perpendicularly to the one end surface portion from the target position toward the other end surface portion, and the one end surface portion is adjacent to the vertical side surface or the vertical line. Alternatively, the forging suspension member has an inclined side surface formed by inclining at a predetermined angle toward the other end surface portion from the parting line. In order to form a suspension arm having a ball joint portion rotatably mounted on a support member supported on the axle side of the automobile via stud bolts and avoiding an interference region with the axle side component by machining. In forged suspension members,
The forged suspension member includes an arm portion, a ball joint portion provided at one end of the arm portion, a vehicle body side engaging portion provided at the other end of the arm portion, the arm portion, the ball joint portion, and the vehicle body. A parting line continuously formed at a predetermined position of the side engagement portion,
The ball joint portion includes one end surface portion, the other end surface portion facing the one end surface portion, and a side surface portion formed over the other end surface portion and the one end surface portion,
The parting line of the ball joint portion is located at a position in the range of the interference region on the side surface portion, on one peripheral side of the one end surface portion or the other end surface portion, and a preset target of the side surface portion. A forged suspension member formed toward a position.   The ball joint section may have a cross section at a position along the parting line in a perfect circle or an approximate perfect circle shape in a neutral direction of the stud bolt or a direction orthogonal to the one end face portion, and With the inclined side surface having a slope angle of a draft angle inclined from the cutting line, the inclined side surface, and the both end surface portions having a compound curvature circular shape having a plurality of curvatures surrounded by the vertical side surface or the vertical line. The forged suspension member according to claim 1 or 2, further comprising:   The forged suspension member according to claim 1, wherein the target position is formed at a position on the vertical side surface or the vertical line position where there is no increase in thickness due to draft.   The parting line in the ball joint portion is linear from the parting line in the arm portion to the target position, or linearly from the parting line in the arm portion to the target position via a curve, or 5. The forged suspension member according to claim 1, wherein the forging suspension member is formed by linearly extending a parting line of the arm portion from an extended position to the target position. 6. .   The forging suspension member according to claim 1, wherein the parting line is formed at an arbitrary position from an upper end side to a lower end side on the side surface of the arm portion. 7. .   The forged suspension member according to any one of claims 1 to 6, wherein a vertical direction of the vertical side surface or the vertical line is a direction parallel to a neutral direction of the stud bolt.   The forged suspension member according to any one of claims 1 to 7, wherein a target position of the ball joint on the parting line is located at a position removed by machining. A suspension arm formed by machining the forged suspension member according to any one of claims 1 to 8,
When the radius of the ball ball diameter of the stud bolt engaged with the ball joint of the suspension arm is R1, and the distance from the center of the ball joint to the outermost part in the interference area of the ball joint is distance R2, A suspension arm, wherein the ball joint portion is formed in a ratio represented by 1.2 <R2 / R1 ≦ 1.9.   The suspension arm according to claim 9, wherein the stud bolt has a pull-out strength and a push-out strength of 25 kN or more.   The said forged suspension member is made of an Al-Mg-Si-based aluminum alloy having an average area ratio of sub-crystal grains in the structure of 60% or more and a 0.2% proof stress of 290 MPa or more. The suspension arm according to claim 10. A forging die for forging a forged suspension member according to any one of claims 1 to 8,
The parting line in the ball joint portion is formed on a peripheral side of the one end surface portion or a peripheral side of the other end surface portion toward a target position of a side surface portion which is a furthest end portion from the parting line of the arm portion. A forging die for a forged suspension member, wherein the forging die is provided with a mold surface. A forging die for forging a forged suspension member according to any one of claims 1 to 8,
In the forging die, the parting line in the ball joint portion is directed to a target position on a side surface portion that is an end portion far from the parting line of the arm portion on a peripheral side of one end surface portion or a peripheral side of the other end surface portion. Providing a parting surface to be formed, and setting the parting surface to be inclined at a predetermined angle with respect to the forging press direction in the arm part and the ball joint part,
The side surface portion at the target position is set so as to be in a direction orthogonal to the one end surface portion of the ball joint portion, or to be parallel to a neutral direction of the stud bolt. Forging die for forging suspension members.

Images